Comment by rattray | Hacker News Reader

Comment by rattray | Hacker News Reader

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Hmm, okay, thanks, that's reassuring!

To share more on where I'm coming from, one example: when I look at things like Yesod's "Hello world" section in "Getting Started", the first thing I see is 4 pragmas: https://www.yesodweb.com/book/basics and I just don't have much information on what those are, how commonly they're used[0], whether (and why) I need them to use Yesod, etc.

I have a kneejerk reaction to that since I want to be able to understand the code I'm seeing and I'm not sure what's going on behind the scenes. But kneejerk reactions are bad, so I'll give them the benefit of the doubt next time!

[0] Well, I definitely understand OverloadedStrings and TemplatHaskell to be very widely used, and think I get their gist.

TemplateHaskell and QuasiQuotes are very closely related. They're where that square bracket syntax comes from:

    [whamlet|Hello World!|]

I would say that they're closer to the situation you're concerned about - they're very much like C++ templates, and equally controversial for exactly the same reasons. Still, I don't usually think of C++ templates, or Haskell ones, as being a different style per-se, just an advanced feature to use sparingly, mostly just when they'll save you from writing a bunch of boilerplate.

For completeness - Overloaded strings are the Haskell parallel to Python's b-string, f-string, u-string, etc. TypeFamilies are "let me write functions over types", which sounds like it would be dramatic enough to introduce a different coding style, but since it, like other extensions, needs to play nicely with the type inference, it doesn't conflict with other extensions, so things mostly just work as you'd expect. Since extensions generally work nicely together, most people just turn on "the usual" extensions for the whole project (all the more reason we need a new standard), and only add explicit pragmas in files to call out heavyweight things like TemplateHaskell. In tutorials you're more likely to see them all listed at the top, though, to be clear about what's being used.

Thanks!

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